The present disclosure relates to semiconductor structures, and particularly to semiconductor structures including a metal-oxide-semiconductor field effect transistor (MOSFET), a substrate contact structure, and a gate contact structure, and methods of manufacturing the same.
As semiconductor devices shrink in each generation of semiconductor technology, formation of contact structures to source and drain regions and gate electrodes of a field effect transistor become challenging because such contact structures not only need to provide reliable electrical contact to the source and drain regions or the gate electrodes, but also need to avoid electrically shorting to other components or among themselves. The challenge is especially severe in replacement gate integration schemes, in which disposable gate structures are replaced with replacement gate structures including a high-k dielectric material gate dielectric and a metallic gate electrode. Sequentially forming different groups of contact structures can lead to electrical shorts among components due to lithographic misalignment during multiple lithographic exposure steps and distortion of patterns due to resist shadowing. Thus, a reliable metal interconnect structure that avoids electrical shorting and pattern distortion is desired.